Hi all, may be this is a simple/stupid/repetitive question, but I don't know how to solve it. I'm trying to connect two sockets on Pharo 1.2.1, with following code: Server -------- |port msg| port:= 9191. Transcript open; show: 'testing --- ' ; cr. listening := true. [self isListening] whileTrue: [ |server connectedClient| server := Socket newTCP. server listenOn: port. connectedClient := server waitForAcceptFor: 5. connectedClient ifNil: [msg:='TimeOut'] ifNotNil:[ msg := 'Data: ', connectedClient receiveData connectedClient closeAndDestroy ]. Transcript show: msg ; cr. server closeAndDestroy. ]. Transcript show: 'end ------'. ------------ Client ------------ | s | s:= Socket newTCP. s connectToHostNamed: 'localhost' port: 9191. s sendData: 'Hello'. s closeAndDestroy --------- First I run the server and later the client and get the following error: Error: primAcceptFrom:receiveBufferSize:sendBufSize:semaIndex: failed I attach a screenshot of the debug window. Thanks in advance.